During strenuous physical activity, such as running races, and especially those involving distance races of 10 kilometers or more, a runner's body can become dehydrated, unless the lost fluid is replaced. During such exercise, particularly in heat, a great metabolic demand is placed on the human body. During such exercise, sweat is lost from the body, which can produce a state of dehydration or hypohydration. Dehydration, is associated with a reduction in the plasma volume in a cell. Associated with dehydration is an impairment of body heat dissipation and endurance performance. To maintain the body's physical capabilities, it is essential that water, electrolytes, carbohydrate, and other nutrients be provided in a timely and appropriate manner. Fluid replacement during physical activity has been shown to be effective in preventing dehydration and hyperthermia.
In marathon races, there may be as many as twenty (20) fluid, water, replenishing stations spaced at convenient intervals throughout the race course. These stations are typically manned by individuals who hand out plastic or paper liquid containers containing water or other suitable fluids. As the runner passes these water stations, he attempts to maintain his pace by maintaining his or her stride, breathing rhythm and air intake volume. As the runner takes the container and attempts to drink, a majority of the fluid is spilled. If the liquid contains fruit sugars or electrolytes, the runner's skin and clothes become encrusted with sticky and crystalline residue which causes discomfort and reduces concentration and efficiency by skin chafing and irritation.
Runners also frequently choke when attempting to drink from a conventional cup container. Some runners have resorted to carrying a plastic straw with them which they carry in their shorts or behind their ear. This tends to reduce spillage, however, the straw may form a seal on the bottom of the cup causing liquid intake to stop momentarily and causing the runner to disrupt his breathing pattern, or it may poke the back of the throat of the runner. The straw is also easily lost. To date, there has been no effective device which will permit a runner to intake fluid without breaking stride or spilling large quantities of liquid during the intake process.